1. Field of Invention
The present invention relates to the transporting of books during an intermediate stage of the production thereof and particularly to the conveying of batches of previously ordered paper sheets, the sheets being interconnected by mechanical binders, to a position where covers are applied thereto. More specifically, the present invention is directed to a conveyor mechanism which affords stable transport, to a cover application station, of batches of loose sheets which are retained in the order by means of mechanical binding elements. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
In the manufacture of books, conveyor mechanisms are employed to transport partially finished books between work stations. Often, as a book nears completion, the conveying thereof becomes more difficult. This is particularly true in the case of books that are comprised of loose sheets which are provided with a series of holes along one edge, the sheets being retained in prearranged order by means of generally round mechanical binding elements. Examples of "books" having such construction which must be transported to a cover application station are notebooks and calendars, such "books" often being provided with reinforced front and back end sheets. The binding elements employed in such "books" may be fabricated from wire or plastic. Thus, in the technique known in the trade as "comb" binding, a wire is formed into a linear array of parallel teeth, each tooth defining a double ring. Each of these double rings, at one end, has a short section of wire which extends diagonally with respect to the rings to interconnect the rings of each tooth. In the course of assembly of such a mechanically bound "book", a series of holes is punched in the batch of sheets, the teeth of the comb are passed through these holes, and the teeth are bent in the shape of a circle. The tips of the teeth extend into facing interstices in the binder, these interstices being left as a result of the formation of the teeth, so as to define a discontinuous, generally linear seam. Such a comb binding is indicated at 3 in application FIG. 1.
In accordance with an alternative mechanical binding technique, the binding element is fabricated from plastic and has a support section with teeth extending outwardly therefrom. After the teeth of such a plastic binding element have been inserted through the holes in the stacked sheets comprising the "book", the binding element is formed into a cylindrical shape and a seam is defined by abutting ends of cooperating teeth.
Batches of paper sheets held together by the above-described mechanical binding elements are often encased in a rigid book cover. This "casing-in" operation is performed by adhesively securing the end sheets of the "book" to the inside of the leaves of the book covers. In order to deliver the bound "book" to a casing-in machine, the "book" must be supported astride saddle plates of an endless conveyor. This, however, places the straight edge of the saddle plate under the round teeth of the binding element. The casing-in operation includes the application of paste to the end sheets of the "book" and the subsequent rolling of the cover onto the "book" by means of lateral pressure rollers. These rollers first move upwardly, while engaged with the cover, and then change direction and roll the book cover onto the "book".
The lack of stability of a mechanically bound "book" on a saddle plate presents a problem of long standing in the art. This problem manifests itself in the possibility of relative movement between the edge of the saddle plate and the round teeth of the binding element, any such movement resulting in the end sheets of the "book" not contacting the book cover at right angles or the lateral distances being uneven. Also, the binding elements often cannot be made parallel to the backs of the book covers. Any such misalignment results in an unacceptable product.